Touch Pad Module Having a Circuit Board Including a Recessed Area and Electronic Device Using the Same

1. A touch pad module suitable for an electronic device, the touch pad module comprising: a circuit board, having a first surface and a recessed area below the first surface; a trigger element standing on the first surface of the circuit board across the recessed area; and a gap exists between the trigger element and the first surface of the circuit board, and an amount of deformation of the trigger element towards the recessed area is larger than the gap; wherein when the trigger element deforms by an external force, at least a part of the trigger element is located in the recessed area; and wherein the recessed area includes a through hole, and when the trigger element is deformed by the external force, a bottom portion of the trigger element is located in the through hole.

2. The touch pad module as claimed in claim 1 , wherein the circuit board further comprises: a ground area surrounding the recessed area, wherein the trigger element is in constant contact with the ground area; and a touch and press operation area disposed in the recessed area, wherein when the trigger element being is deformed by the external force, the trigger element contacts the touch and press operation area to electrically conduct the ground area and the touch and press operation area.

3. The touch pad module as claimed in claim 2 , wherein the circuit board further comprises an airflow passage connected between the recessed area and a lateral surface of the circuit board.

4. The touch pad module as claimed in claim 2 , wherein the circuit board further comprises: a through hole located in the recessed area, the touch and press operation area surrounding the through hole.

5. The touch pad module as claimed in claim 1 , wherein the circuit board further comprises: a ground area surrounding the recessed area, and the trigger element being constantly contacted to the ground area; and a touch and press operation area disposed between the ground area and the recessed area and surrounding the recessed area, wherein when the trigger element is deformed by the external force, the trigger element and the touch and press operation area are in contact with each other to electrically conduct the ground area and the touch and press operation area.

6. The touch pad module of claim 5 , wherein the ground area and the touch and press operation area are located on one same plane of the circuit board.

7. The touch pad module as claimed in claim 1 , wherein the trigger element is a metal reed.

8. An electronic device, comprising: a housing, having an opening; a touch pad, disposed in the housing, a touch surface of the touch pad exposing the housing from the opening; a circuit board, disposed in the housing and having a first surface and a recessed area below the first surface; and a trigger element, standing on the first surface of the circuit board across a top of the recessed area, and disposed between the touch pad and the circuit board; and a gap exists between the trigger element and the first surface of the circuit board, and an amount of deformation of the trigger element towards the recessed area is larger than the gap; wherein when the trigger element deforms by an external force, at least a part of the trigger element is located in the recessed area; and wherein the recessed area includes a through hole, and when the trigger element is deformed by the external force, a bottom portion of the trigger element is located in the through hole.

9. The electronic device as claimed in claim 8 , wherein the circuit board further comprises: a ground area surrounding the recessed area, wherein the trigger element is in constant contact with the ground area; and a touch and press operation area, located in the recessed area, wherein when the trigger element is deformed by the external force, the trigger element contacts the touch and press operation area to electrically conduct the ground area and the touch and press operation area.

10. The electronic device as claimed in claim 9 , wherein the circuit board further comprises an airflow passage, connected between the recessed area and a lateral surface of the circuit board.

11. The electronic device as claimed in claim 9 , wherein the circuit board further comprises: a through hole, located in the recessed area, the touch and press operation area surrounding the through hole.

12. The electronic device as claimed in claim 8 , wherein the circuit board further comprises: a ground area, surrounding the recessed area, and the trigger element being constantly contacted against the ground area; and a touch and press operation area disposed between the ground area and the recessed area and surrounding the recessed area, wherein when the trigger element is deformed by the external force, the trigger element and the touch and press operation area are in contact with each other to electrically conduct the ground area and the touch and press operation area.

13. The electronic device as claimed in claim 12 , wherein the ground area and the touch and press operation area are located on one same plane of the circuit board.

14. The electronic device as claimed in claim 8 , wherein the trigger element is a metal reed.